Apparatus and Method for Sending and Receiving Broadcast Signals

1. A broadcast signal receiver comprising: a synchronizer/demodulator configured to perform signal detection and Orthogonal Frequency Division Multiplexing (OFDM) demodulation on a received broadcast signal; a frame parser configured to derive service data by parsing a signal frame of the received broadcast signal based on a number of carriers of the signal frame; a demapper and decoder configured to convert the service data into a bit domain and perform deinterleaving; and an output processor configured to receive the service data and output a data stream, wherein the synchronizer/demodulator further comprises a pilot signal detecting module configured to detect a pilot signal including Continual Pilots (CPs) and Scattered Pilots (SPs) from the received broadcast signal, and wherein the number of carriers of the signal frame is determined as a maximum number of carriers or determined by reducing a unit from the maximum number of carriers, the unit is obtained by multiplying a control unit value by a reducing coefficient and the control unit value corresponds to a predetermined number of carriers which are determined based on a Fast Fourier Transform (FFT) size.

2. The broadcast signal receiver of claim 1 , wherein the control unit value corresponds to 96 when an 8K FFT size is used, 192 when a 16K FFT size is used and 384 when a 32K FFT size is used.

3. The broadcast signal receiver of claim 1 , wherein the CPs include a common CP set and an additional CP set.

4. The broadcast signal receiver of claim 3 , wherein the common CP set includes a first CP set for a 32K FFT mode, a second CP set for a 16K FFT mode, and a third CP set for an 8K FFT mode, and the first CP set, the second CP set, and the third CP set are generated by using a predetermined first reference CP set.

5. The broadcast signal receiver of claim 4 , wherein the first CP set is generated by adding a second reference CP set to the first reference CP set and the second reference CP set is generated by reversing and shifting the first reference CP set.

6. The broadcast signal receiver of claim 5 , wherein the second CP set is generated by using CPs of every second index from CPs included in the first CP set.

7. The broadcast signal receiver of claim 5 , wherein the third CP set is generated by using CPs of every fourth index from CPs included in the first CP set.

8. The broadcast signal receiver of claim 3 , wherein the additional CP set is placed at a carrier location of the SPs for ensuring a constant number of data carriers in every data symbol of the signal frame, and wherein the additional CP set depends on an SP pattern and the FFT size.

9. The broadcast signal receiver of claim 8 , wherein the additional CP set for a specific SP pattern and a specific FFT size is placed differently according to the reducing coefficient.

10. A method for receiving a broadcast signal, the method comprising: performing signal detection and OFDM demodulation on a received broadcast signal; deriving service data by parsing a signal frame of the received broadcast signal based on a number of carriers of the signal frame; converting the service data into bit domain and performing deinterleaving; and receiving the service data and outputting a data stream, wherein the performing signal detection and Orthogonal Frequency Division Multiplexing (OFDM) demodulation further comprises detecting a pilot signal including Continual Pilots (CPs) and Scattered Pilots (SPs) from the received broadcast signal, and wherein the number of carriers of the signal frame is determined as a maximum number of carriers or determined by reducing a unit from the maximum number of carriers, the unit is obtained by multiplying a control unit value by a reducing coefficient, and the control unit value corresponds to a predetermined number of carriers which are determined based on a Fast Fourier Transform (FFT) size.

11. The method of claim 10 , wherein the control unit value corresponds to 96 when an 8K FFT size is used, 192 when a 16K FFT size is used and 384 when a 32K FFT size is used.

12. The method of claim 10 , wherein the CPs include a common CP set and an additional CP set.

13. The method of claim 12 , wherein the common CP set includes a first CP set for a 32K FFT mode, a second CP set for a 16K FFT mode, and a third CP set for an 8K FFT mode, and the first CP set, the second CP set, and the third CP set are generated by using a predetermined first reference CP set.

14. The method of claim 13 , wherein the first CP set is generated by adding a second reference CP set to the first reference CP set and the second reference CP set is generated by reversing and shifting the first reference CP set.

15. The method of claim 14 , wherein the second CP set is generated by using CPs of every second index from CPs included in the first CP set.

16. The method of claim 14 , wherein the third CP set is generated by using CPs of every fourth index from CPs included in the first CP set.

17. The method of claim 12 , wherein the additional CP set is placed at a carrier location of the SPs for ensuring a constant number of data carriers in every data symbol of the signal frame, and the additional CP set depends on an SP pattern and the FFT size.

18. The method of claim 17 , wherein the additional CP set for a specific SP pattern and a specific FFT size is placed differently according to the reducing coefficient.